Osteogenesis Imperfecta, Tarda (OI)

Michael P. D'Alessandro, M.D.
Peer Review Status: Internally Peer Reviewed

Etiology/Pathophysiology:
Due to abnormal formation of osteoid, matrix, and collagen and associated with osteoblastic dysfunction. Usually autosomal dominant but often due to spontaneous mutations. Accounts for 90% of OI disease.

Pathology:
Not applicable

Imaging Findings:
See fractures of lower extremities with bowing of long bones. Fractures have exuberant callus formation when healing. Bones have thin cortices and the bone is osteopenic with a decreased trabecular pattern. Genu valgum (knock knees) and coxa vara due to femoral neck fractures are seen. Vertebral body osteopenia leads to biconcave compression deformities. Wormian bones are present. Basilar impression and overhanging occiput (platybasia) can develop.

DDX:
Wormian Bones

• OI
• Cleidocranial dysostosis
• Pycnodysostosis
• Congenital hypophosphatasia
• Congenital hypothyroidism (cretinism)
• Normal individual

References:
See References Chapter.

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